Problem: Find the output, $b$, when the input, $a$, is $6$. $b = -1-7a$ $b=$
Explanation: To find the output, ${b}$, we need to substitute ${6}$ into the equation for ${a}$. $\begin{aligned} {b}&=-1-7{a}\\\\ {b}&=-1-7\cdot{6}\\\\ &=-1-42\\\\ &={-43} \end{aligned}$ When the input is $6$, the output is $-43$.